1. Field of the Invention
The invention relates generally to the field of digital data processing systems and more specifically to systems comprising clusters of individual computer systems. The invention comprises a cluster console unit for connection to the individual computer systems comprising the cluster for monitoring the operations and status of the computer systems.
2. Description of the Prior Art
A computer system typically comprises three basic elements: namely, a memory element, an input/output element and a processor element. The memory element stores information in addressable storage locations. This information includes data and instructions for processing the data. The processor element transfers information to and from the memory element, interprets the incoming information as either data or instructions and processes data in accordance with the instructions. The input/output element also communicates with the memory element in order to transfer input data to the system and to obtain processed data from it.
Initially, computer systems were generally standalone systems; that is, a single processor would communicate only with its own memory and with its own input/output units. To increase the processing speeds and enhance reliability and availability of the system to users, data processing systems have recently been developed which include multiple processors units. In some such multi-processing systems, the processors are connected directly together or through a random-access memory unit. The diverse processors would have access to shared data in the memory unit. In some arrangements, the processors may share such peripheral devices as disk and tape storage units, printers, video display terminals, telecommunications interface equipment and the like, and in others each processor may have separate such equipment.
More recently, efforts have been made to interconnect a number of such computer systems and peripheral equipment which may be shared by the diverse computer systems to form a single digital data processing system. In one interconnection scheme, each computer system and shared peripheral unit is connected to and communicates over a network. In the network, the computer systems and shared units transmit messages in the form of packets of information. The computer systems that are connected into the network are able to share data and programs through the shared disk and tape drives.
An alternate interconnection mechanism that is particularly useful for computer systems that are not so widely used is to cluster. A cluster typically includes fewer communicating units, that is nodes than can be accommodated by a network.
One problem arises, however, by providing multiple nodes interconnected in a cluster. The nodes comprising the cluster may be located in diverse locations and the system console for each computer system is typically colocated with its associated computer system. The system console provides the operator interface to the system. It allows the operator to examine and deposit data in the system, to halt the operation of the processor or step it through a sequence of program instructions. It enables an operator to initialize the computer system through a bootstrap procedure and perform various diagnostic procedures. However, locating each system console with its associated computer system would require the operator to move to the various locations of the computer systems to perform the required tasks, or several operators would be required for the various locations. Having an operator at each location adds to the cost of operating the cluster data processing system. However, having only a single operator who must move from location to location to determine the operating status of the computer system at each location precludes determining the operating status of all of the computer systems at one time. In some emergency situations, this may be undesirable.